6/6 On the Local and Relative Geology of Singapore, [July, 



seemed (o lead, to the Bataviaash Genootschap van Kunsten en Weten- 

 schappen, in whose Transactions, the President writes me, it will appear- 

 In this paper I had been led to some views with which I find Mr. 

 Darwin had been occupied, and which are developed in the chapter on 

 plutonic and metamorphic rocks in his geological observations on South 

 America, of which, though bearing the same date as my paper, I did 

 not receive a copy till about a fortnight ago. The germ of his ideas 

 is however contained in his Volcanic Islands, which I have referred to 

 in my paper. As I have also considered the subject from some other, 

 and, as I believe, new points of view, I shall send you a copy of the 

 paper in English, the Batavian Transactions being in Dutch.* The 

 coast of the mainland behind P. U'bin consists of rocks some of which 

 would be called plutonic and others volcanic like those of Pulo U'bin, 

 but the whole are undoubtedly of the same contemporaneous origin. 

 At Runto, in the estuary of the Johore River, sandstone, similar to that 

 of the Singapore Red cliffs, and, like it, remarkable for being nearly 

 horizontal, is exposed. Further up the River the rocks exposed are 

 of a decomposed felspathic character, and exactly resemble some of 

 those of the hypogene tract of Singapore. At one place a hard 

 ferruginous crust about 9 inches thick overlaid a decomposed felspathic 

 rock. Pulo Tikong, Besar and Kechil, consist chiefly of sandstones 

 and in part of shales, often greatly altered by volcanic action. On the 

 coast to the S. E. near Johore Hill, or at Tanjong Pingrang, are found, 

 within a small compass, soft shale or clay, — clay indurated so as to 

 resemble, or become, chert, — conglomerate highly indurated and parti- 

 ally transformed, — quartz rock, — and traces of blackish brown slags, — 

 indicating various degrees, and even some difference in the mode of 

 the volcanic action. 



The connection between the crystalline and sedimentary rocks of the 

 district is susceptible of two explanations. We may either consider 



* In a general descriptive sketch of some portion of the Straits of Malacca which I 

 sent to the Geographical Society some time ago, I mentioned the singular grooved rocks 

 at the Chinese Quarries on P. U'bin, and hazarded some conjectures respecting- their 

 origin— when I wrote that paper I had made only one flying visit to the Quarries and 

 was under the impression that the deep channels were confined to this locality. My 

 first geological visit subsequently at once undeceived me. In the paper forwarded to the 

 Batavian Society, I have shewn how these channels have resulted from the original 

 structure of the rock under ordinary decomposing and eroding influences. 



